Inhalers are common devices for delivering various medications (including drugs and other therapeutic agents) to a patient (also referred to herein as a user) in an inhaled aerosol form referred to herein as inhalant. Many medical conditions and diseases may be treated with inhalers including respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD) as well as non pulmonary conditions including diabetes. COPD which includes emphysema and chronic bronchitis is a particularly debilitating disease affecting as many as 24 million Americans and killing more than 100,000 each year. It involves thickened and narrowed lung airways and excess mucous. Symptoms include persistent coughing and severe shortness of breath.
Inhalers provide a benefit of ensuring any drug or other therapeutic agent distributed as an inhalant is quickly delivered to a target pulmonary site (e.g., the bronchial tubes in the case of asthma) or absorbed into the bloodstream, as the human respiratory system is well adapted to absorb aerosol or other inhalants into the blood stream. In fact, many large-molecule drug compounds including proteins and peptides are easily absorbed by the lungs, and once absorbed in the deep lung, they pass readily into the bloodstream (through a single-cell layer known as the pulmonary epithelium) without the need for enhancers that are required by other noninvasive routes.
However many patients who use inhalers have compromised respiratory function such that they are not able to take a deep or forceful enough breath for the inhalant to reach the bronchial tubes, let alone the deep lung or other target site in sufficient quantities to treat the particular condition (either in terms of the drug having the desired affect at the site or being absorbed in sufficient quantities into the blood stream to have the desired effect on another target site). This is particularly the case for COPD where patients have severe shortness of breath and frequent bouts of coughing. Even for non respiratory-compromised patients, variations in breathing technique can result in significant variation in the amount of drug delivered to the target site including deep into the lung resulting in possible inconsistent dosing from breath to breath. Thus, there is need for an improved inhaler.